Sono-buoy stabilizer



United Patent Ofi ice Eatented Apr-.30, 1957 SONO-BUOY STABILIZER Lawrence T. Carapellotti, Philadelphia, Pa., assignor, by mesne assignments, to the United States -ofaAmenca as represented by the Secretary of the Navy' A lication-Se tember so, 19s3,serta11 io.ss3,42 4

' 4'Claims. c1. 9-8

This invention relates to sono-buoys, and more particularly to apparatus for stabilizing sono-buoys in rough seas and high winds.

To obtain stability of a sono-buoy when floated in water, it is necessary to place the center of gravity of the buoy Well below the center of buoyancy. In the past, this has been accomplished by adding weight to the lower sections of the buoy or by adding weight to the hydrophone. The addition of weight to the structure is, of course, undesirable for use aboard ships or aircraft where weight factors are serious problems.

It is, therefore an object of this invention to increase the stability of buoys, and particularly sono-buoys, without adding weight to the assembly.

It is a further object of this invention to provide a sono-buoy which will be stable in rough seas and in high winds and which does not involve the use of significant weights or cumbersome devices.

Still another object of this invention is the provision of a sono-buoy wherein the static center of gravity is not materially altered, but wherein the dynamic center of gravity is placed .well below the center of buoyancy.

Other objects and advantages of this invention will become apparent and the invention will be better understood from the following description and claims when taken in connection with the accompanying drawings in which:

Figure 1 schematically represents the preferred form {of my invention wherein the hydrophone is shown in the stored inoperative position; and

Figure 2 is a view showing the sono-buoy floated in water in its suspended operative position.

Referring now to the drawings, there is shown a sonobuoy 10 comprising an enclosed cylindrical transmitting section 11, having an extended skirt forming a chamber, or hydrophone section 12. The transmitting section is made entirely watertight by means of the upper wall 21 and the wall 13. mounted on the wall 21 by means of any suitable sealing device 31. For storage, the extended skirt is closed at the bottom end (as shown in Figure l) by means of the wall 29, which has a threaded bore therein, and a threaded plug 17. The hydrophone 19 of the sono-buoy is stored within theenclosed section 12, in the manner shown in Figure 1, when the sono-buoy is not in use, and, as shown, the hydrophone is connected by means of a line 1% to a piston 15. v

The piston is mounted in its storedposition, as shown, by means of spring clips 22, or other suitable'devices. The section 12 has been provided with small vent holes 14, for a purpose to be hereinafter described.

When the sono-buoy 10 is to be used for underwater detection, the plug 17 is removed and the sono-buoy is floated. As shown in Figure 2, the hydrophone 19 drops outof the section 12 and pulls the piston 15 to the position shown to reseal the section. For practical purposes, the piston 15 need not be watertight. It is understood that many other arrangements for sealing the device tliesonoi-buoy isifirst floated, the vent holes Mare-beneath the water line. The vent holes, are relatively small and,. thus; slowly permit" the section12 to become filled with: water.

The antenna 30' for the transmitter is It isiunderstoodthat the center" of buoyancy of any body is at thecenter. of gravity of the displaced-volume Ofithewater. The center of buoyancy'shifts its position both vertically and sidewise as a floating 1 body tips and the total upward pressure of water on a floating body may be regarded as concentrated through the center of buoyancy. It is well known that stability of a floating body demands that when the body is tipped, a vertical line through the new center of buoyancy must pass the center line above the center of gravity of the body. The center line is the vertical line passing through the center of gravity when the body is in equilibrium. When it does so pass, both the weight and the buoyancy tend to right the floating body. When it passes below the center of gravity, both the weight and the buoyancy tend to overturn it.

Assuming that the structure as shown in Figure 2 were constructed with the vent holes 14 sealed, it is seen that the center of gravity of the structure is high because of the relative weights of the sections 11 and 12 and it would be in a position such as shown. It is also clear that since the center of buoyancy is at the center of gravity of the displaced volume of the liquid, the center of buoyancy will be below the center of gravity of the buoy. In the assumed condition of the vent holes 14, it is noted that if the buoy tips, a small angle of tipping will cause a vertical line passing through the new center of gravity to pass below the center of gravity and, therefore, the buoy is unstable.

This condition of instability can be corrected by shifting the center of gravity of the buoy. Since the weight of the buoy is a critical factor, the shifting of the static center of gravity, i. e., the center of gravity of the body in its stored position, by adding weight to the hydrophone section 12 is unsatisfactory. The problem has been solved by the use of the vent holes which permits the filling of the section 12 with water, thereby lowering the dynamic center of gravity, i. e. the center of gravity of the buoy when it is floated.

Since the vents 14 are small, water entering the hydrophone section 12 is substantially trapped and the dynamic center of gravity of the sono-bu-oy assembly 10 will be very close to the center of gravity of the sonobuoy assembly plus the water trapped in the hydrophone It is to be understood that the proceeding disclosure relates only to a schematic representation of a preferred embodimentof this invention and that many modifications in size, shape and arrangement will immediately become apparent to any one skilled in the art. I, therefore, desire that my invention shall not be limited except insofar as ismade necessaryby the prior art and by the scope of the appended claims.

I claim as my invention:

1. In a buoy, an upper enclosed chamber housing a weight therein, a lower chamber joined to said upper chamber, said lower chamber having an open end remote from said upper chamber and a weight therein adapted to pass through said opening, a first removable closure member for said opening, a second closure memher for said opening, said second closure member being disposed in said lower chamber above said weight, flexible means connecting said weight and said second closure member, and orifices in said lower chamber near the top thereof, whereby when said first closure memberv is removed from said opening and said buoy is'floated, said weight will pass through said opening and be suspended beneath said buoy by said flexible means, said; second closure member will lodge on and seal said opening, and

said lower chamber will become substantially filled with water. v

2. In a buoy having an upper sealed compartment and a lower compartment, a weight in said upper vcomparting said second weight below said how, means sealing ment, a second weight in said lower compartment, an 7 opening in the lower end of said lower compartment,

means permitting said second weight to passthnough said opening when said buoy is floated, means suspendsaid opening after said weight has passed through said opening, and means to permit water to enter and substantially fill said lower compartment.

3. The combination defined in claim 2 wherein said sealing means comprises a disc, said suspending means being attached to said disc. i

4. The combination of claim 2, wherein said means permitting the entryyof water comprises small vent holes near the upper end of said lower compartment.

References Cited in the file of this patent I I UNITED STATES PATENTS 203,399 Wyckofi May 7, 1878 366,077 Delany July 5, 1887 2,641,751 Mason June 9, 1953 

